There are so many alternative sweeteners available now that they seem to be elbowing sugar right off the supermarket shelf. But what's so wrong with sugar? At just 15 calories per teaspoon, "nothing--in moderation," says Lona Sandon, R.D., an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center in Dallas. "The naturally occurring sugar in an apple is fine, but if we can reduce some of the added sugar in our diet, we can remove some of the empty calories." Less than 25 percent of your daily calories should come from the added sugar in foods like cookies, cereal, and ketchup, she says. To satisfy your sweet tooth--especially if you're counting calories, limiting carbs, or dealing with diabetes--try these options:

SWEETLEAF AND TRUVIA

What they are: These sugar alternatives are the latest made from stevia, an herb found in Central and South America that is up to 40 times sweeter than sugar but has zero calories and won't cause a jump in your blood sugar. Stevia was slow to catch on because of its bitter, licorice-like aftertaste, but makers of Truvia and SweetLeaf have solved this problem by using the sweetest parts of the plant in their products.

Where to find them: In grocery stores and natural-food stores throughout the country and online at sweetleaf.com
and truvia.com.

How to use them: Both work well in coffee and tea or sprinkled over fruit, cereal, or yogurt. You can't substitute stevia-based products for sugar in baked goods, though, because these products are sweeter than sugar and don't offer the same color and texture. Makers of SweetLeaf promise to come out with a baking formulation soon.

Health Rx: "Truvia's one of the most promising alternatives out there," says nutritionist Jonny Bowden, Ph.D., author of The Healthiest Meals on Earth . "Right now, it looks safe. It tastes just like sugar and has almost no glycemic index, which means it won't spike your blood sugar."

What it is: Three naturally occurring sugars--fructose, the sugar in fruit; sucrose, or table sugar; and lactose, the sugar in milk--are blended to create this sweetener. While individually the sugars are fully caloric, when blended in Whey Low they interact in such a way that they aren't completely absorbed into the body. As a result, at four calories per teaspoon, Whey Low has one quarter of the calories and less than one third of the glycemic index of sugar, so you're less likely to crash after consuming it. It's available in varieties similar to granular sugar, brown sugar, maple sugar, and confectioners' sugar.

Where to find it: At grocery stores, like Whole Foods Market, online at wheylow.com, and in some baked goods at bakeries around the country.

How to use it: "Whey Low's flavor and texture are very similar to sugar's and it's easy to use," says Yasmine Sandhu, the pastry chef at Rock Creek, a restaurant in Washington, D.C., which uses Whey Low to keep calorie counts down. "I've substituted it into all my recipes as if it were sugar. The only product I've had trouble with is meringue--it browns a little quicker and doesn't set quite as well."

Health Rx: "Whey Low's creator argues that the way the sugars interfere with each other means that you get all of the sweet but many fewer calories than sugar," says Thomas Castonguay, Ph.D., a professor of food science at the University of Maryland in College Park. "We're testing that process here in the lab, and the preliminary results look promising."

What it is: This naturally occurring sugar alcohol is found in foods such as beets, berries, and corn. Xylitol tastes almost as sweet as sugar but is only partially absorbed by the body, so it has only about nine calories per teaspoon and a lower glycemic index.

How to use it: Substitute it for sugar in small amounts in tea or coffee. If you use it for baking, it's recommended that you substitute it for only half of the sugar called for in a recipe.

Health Rx: Xylitol prevents bacteria from causing plaque to stick to teeth, which is why it's often used in sugar-free gum and can help prevent tooth decay. It can also cause stomachaches, gas, and diarrhea if you have too much of it. "Sugar alcohols aren't digested well by the body," says Bowden. "That's what keeps xylitol from raising blood sugar, but it's also what can give you gas."

What it is: Several types of agave, the plant that's used to make tequila, are blended to create this liquid sweetener.

Where to find it: At natural-food stores, in some grocery stores, like Whole Foods Market, and in various baked goods.

How to use it: "It's great for teas and coffee, but it's a little difficult to bake with," says Sandhu. "I use it at about a third of the capacity of sugar--agave nectar is far sweeter than sugar or honey, so you have to reduce the amount a recipe calls for. I look for recipes that use another liquid sweetener, like honey, as the base. I also tend to lower my oven temperature when I use it because agave nectar browns a bit more. It's probably not the best option out there for beginner bakers."

Health Rx: Agave nectar's benefits are still under debate. "It doesn't raise the blood sugar as rapidly as sugar," says Sandon. "And although it has more calories than sugar--about 20 calories per teaspoon--agave nectar is sweeter, so you can use less of it." There is some concern about agave's high fructose content, however; some experts wonder if it will have the same metabolic effect as high fructose corn syrup (HFCS), which has been blamed for increasing rates of obesity. But experts still don't know whether the large quantities of HFCS we're consuming are partly responsible for America's obesity problem, or whether HFCS just happened to enter the American diet at the same time as negative lifestyle changes that led to weight gain.

The bottom line, say experts: We all could afford a little less sweet in our lives. "If you're eating a lot of foods that have these alternative sweeteners in them, that means you're still probably eating a lot of cookies, cakes, and other processed foods that aren't good for you," says Sandon. "We need to get back to eating more whole foods. Sugar substitutes are not a substitute for a healthy diet."

Rumors persist about the health hazards of artificial sweeteners such as Sweet'N Low, Splenda, and Equal, but several food-safety groups and regulatory bodies, including the FDA, have consistently deemed them safe for consumption.

Sweet'N Low (saccharin) has fewer than four calories in each 1⁄4-teaspoon packet, which is as sweet as two teaspoons of sugar. It's best used in tea, coffee, or other drinks as it reacts differently to baking than sugar does, leading to differences in the volume and texture of foods.

Splenda (sucralose) is 600 times as sweet as table sugar; one packet is as sweet as two teaspoons of sugar. Though sucralose is made from a sugar molecule, it's chemically altered in a lab so it passes through the body unmetabolized. Splenda has no calories and is heat stable, so it's ideal for use in baking.

Equal (aspartame) has the sweetness of two teaspoons of sugar in each 1⁄4-teaspoon packet. Use it only in recipes designed specifically for Equal.